by Lewis Chang, PhD
Ultra-processed foods, or highly-processed foods, are food products manufactured via multiple chemical or mechanical processes that are designed to make them convenient, affordable, palatable, and hygienic. Nutritionally, they tend to be loaded with added sugar, salt, and fat, and devoid of high-quality macronutrients, micronutrients, and fiber. Many ultra-processed foods also contain flavoring agents, artificial colors, cosmetic additives, and preservatives, some of which have exhibited carcinogenic potential in experimental models.1 The packaging may also contain chemicals (such as bisphenol A) with carcinogenic or endocrine-disrupting properties.2
- Examples of ultra-processed foods include, but are not limited to:
- Mass produced packaged breads, snacks, confectionery and desserts
- Sodas and sweetened beverages
- Reconstituted meat products (e.g., chicken and fish nuggets) with added preservatives such as nitrites
- Instant noodles and soups and shelf-stable ready-to-eat meals
Ultra-processed food products contribute to 25-50% of total daily energy intake in many countries, including the US.3,4 An increased intake of these products is not only associated with poorer overall nutritional quality,5 but also higher risks of obesity, dyslipidemia and high blood pressure.6-8 A large cohort study linked increased consumption of ultra-processed foods with a higher risk of cancer.9
Epidemiologists from Sorbonne Paris Cité Epidemiology and Statistics Research Center (France) examined longitudinal dietary data and cancer outcomes from more than 100,000 adult participants from the French NutriNet-Santé Study (a web-based cohort study in France investigating associations between nutrition and health).9 The study analyses found that:9
- Consumption of ultra-processed foods was significantly associated with overall cancer risk
- Specifically, a 10% increase in the proportion of ultra-processed foods in the diet increased the risk of overall cancer and breast cancer by 12% and 11%, respectively
- Consumption of unprocessed foods and minimally processed foods was significantly associated with reduced risk of overall cancer and breast cancer
- The observed associations remained statistically significant after adjusting for multiple potential confounders
This is the first prospective epidemiological study reporting the association between food processing and cancer risk.9 However, individuals who consume significant amount of ultra-processed foods may have other unhealthy behaviors (such as cigarette smoking and physical inactivity) which may contribute to cancer risk. Also, the definition of “ultra-processed food” used in the current study is broad, making it difficult to pinpoint whether certain types of food products contribute to cancer risk more than others. Future prospective cohort studies and investigations of underlying mechanisms would add insights to this important subject.
Why is this Clinically Relevant?
- Ultra-processed foods tend to be calorically dense and nutritionally poor and may contain chemicals with undesirable biological effects
- Increased consumption of ultra-processed foods have been associated with metabolic abnormalities and even cancer9
- Clinicians should encourage patients to minimize consumption of ultra-processed foods and increase intake of fresh, whole foods and minimally processed food for healthful nutrition and overall health
1. Bouvard V, Loomis D, Guyton KZ, et al. Carcinogenicity of consumption of red and processed meat. Lancet Oncol. 2015;16(16):1599-1600.
2. Muncke J. Endocrine disrupting chemicals and other substances of concern in food contact materials: an updated review of exposure, effect and risk assessment. J Steroid Biochem Mol Biol. 2011;127(1-2):118-127.
3. Martinez Steele E, Baraldi LG, Louzada ML, Moubarac JC, Mozaffarian D, Monteiro CA. Ultra-processed foods and added sugars in the US diet: evidence from a nationally representative cross-sectional study. BMJ Open. 2016;6(3):e009892.
4. Poti JM, Mendez MA, Ng SW, Popkin BM. Is the degree of food processing and convenience linked with the nutritional quality of foods purchased by US households? Am J Clin Nutr. 2015;101(6):1251-1262.
5. Martinez Steele E, Popkin BM, Swinburn B, Monteiro CA. The share of ultra-processed foods and the overall nutritional quality of diets in the US: evidence from a nationally representative cross-sectional study. Popul Health Metr. 2017;15(1):6.
6. Rauber F, Campagnolo PD, Hoffman DJ, Vitolo MR. Consumption of ultra-processed food products and its effects on children’s lipid profiles: a longitudinal study. Nutr Metab Cardiovasc Dis. 2015;25(1):116-122.
7. Mendonca RD, Pimenta AM, Gea A, et al. Ultraprocessed food consumption and risk of overweight and obesity: the University of Navarra Follow-Up (SUN) cohort study. Am J Clin Nutr. 2016;104(5):1433-1440.
8. Mendonca RD, Lopes AC, Pimenta AM, Gea A, Martinez-Gonzalez MA, Bes-Rastrollo M. Ultra-Processed Food Consumption and the Incidence of Hypertension in a Mediterranean Cohort: The Seguimiento Universidad de Navarra Project. Am J Hypertens. 2017;30(4):358-366.
9. Fiolet T, Srour B, Sellem L, et al. Consumption of ultra-processed foods and cancer risk: results from NutriNet-Sante prospective cohort. BMJ. 2018;360:k322.